High-resolution IR spectrum of SCF2 from 1000 to 1400 cm-1:: The ν1/ν3+2ν5/ν2+ν3 and ν4/ν2+ν5 interacting states

The infrared spectrum of SCF, was recorded in the 1000-1400 cm(-1) region with a resolution of 2.5 x 10(-3) cm(-1). The rotationally resolved nu(1) and nu(4) band systems were studied for the first time, and altogether 11 500 transitions were assigned. Both fundamentals are involved in strong anharmonic (Fermi) resonances. Effective centers (J = K-a = K-c = 0) of the interacting bands are nu(1) 1366.7117 cm(-1), nu(3) + 2 nu(5) 1365.4257 cm(-1), nu(2) + nu(3) 1311.1491 cm(-1) (a(1) species), and nu(4) 1190.0839 cm(-1), nu(2) + nu(5) 1217.8191 cm(-1) (b(1) species). The strong K-a dependence of the nu(1)/nu(3) + 2 nu(5) level mixing enabled a numerical determination of the interaction constants while the other anharmonic interactions were accounted for by consideration of relative intensities. Deperturbed band centers, anharmonicity constants, and equilibrium and excited state rotational and centrifugal distortion constants were determined. (C) 1999 Academic Press.